The attackers died before getting near the U.S. ambassador and senior Iraqi officials at the festivities, but the blasts capped a particularly deadly week for American and Iraqi forces.

Iraqi police also were searching for an American journalist who was kidnapped Saturday by gunmen who ambushed her car and killed her translator in Baghdad.

Jill Carroll, a 28-year-old freelancer for The Christian Science Monitor, was seized in Baghdad's predominantly Sunni Arab al-Adel neighborhood. Police said she went there to see a Sunni Arab politician.

The escalating violence after the Dec. 15 parliamentary elections -- at least 498 Iraqis and 54 U.S. forces have been killed -- came as Iraq's electoral commission again delayed releasing the results of the vote.

An Internet site known for publishing extremist material from al-Qaida in Iraq leader Abu Musab al-Zarqawi carried a claim of responsibility for Monday's suicide attack, saying it was in revenge for the torture of Sunni Arab prisoners at two detention facilities run by the Shiite-led Interior Ministry.

Another purported al-Zarqawi statement rebuked Sunni Arabs for participating in the parliamentary elections, saying they had "thrown a rope" to save U.S. policy.

Meanwhile, the U.S. military said eight U.S. troops -- including four Alaska Army National Guard members -- and four American civilians died aboard a U.S. Army Black Hawk helicopter that crashed Saturday in northern Iraq.

Sunni Arabs also expressed anger over a raid Sunday by U.S. troops on the Umm al-Qura mosque, Baghdad headquarters of the Association of Muslim Scholars, a Sunni clerical group that is believed to have ties to some insurgent groups.

The mosque is in the al-Adel neighborhood, one of Baghdad's roughest and the same area where the American journalist was kidnapped.

A U.S. military official, speaking on condition of anonymity because of the sensitivity of the situation, said the raid was a necessary immediate response to the kidnapping based on a tip provided by an Iraqi citizen.

Meanwhile, Britain's former U.N. military commander in Bosnia has said Prime Minister Tony Blair should be impeached over his decision to go to war in Iraq.

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Gen. Sir Michael Rose said Blair's claim that Iraq possessed weapons of mass destruction had turned out not to be true, adding that he would have resigned rather than take troops to war on such a flawed case.

"The politicians should be held to account, and my own view is that Blair should be impeached," Rose said in a Channel 4 documentary to be broadcast later in the week. Excerpts of his remarks were released Monday. "That would prevent politicians treating quite so carelessly the subject of taking a country into war."